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/*
* Copyright (C) 2006 Michael Niedermayer <michaelni@gmx.at>
* Copyright (C) 2012 Clément Bœsch <ubitux@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/**
* @file
* Generic equation change filter
* Originally written by Michael Niedermayer for the MPlayer project, and
* ported by Clément Bœsch for FFmpeg.
*/
#include "libavutil/avstring.h"
#include "libavutil/eval.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "internal.h"
typedef struct {
const AVClass *class;
AVExpr *e[4]; ///< expressions for each plane
char *expr_str[4]; ///< expression strings for each plane
int framenum; ///< frame counter
AVFrame *picref; ///< current input buffer
int hsub, vsub; ///< chroma subsampling
int planes; ///< number of planes
} GEQContext;
#define OFFSET(x) offsetof(GEQContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption geq_options[] = {
{ "lum_expr", "set luminance expression", OFFSET(expr_str[0]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "cb_expr", "set chroma blue expression", OFFSET(expr_str[1]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "cr_expr", "set chroma red expression", OFFSET(expr_str[2]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "alpha_expr", "set alpha expression", OFFSET(expr_str[3]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{NULL},
};
AVFILTER_DEFINE_CLASS(geq);
static inline double getpix(void *priv, double x, double y, int plane)
{
int xi, yi;
GEQContext *geq = priv;
AVFrame *picref = geq->picref;
const uint8_t *src = picref->data[plane];
const int linesize = picref->linesize[plane];
const int w = picref->width >> ((plane == 1 || plane == 2) ? geq->hsub : 0);
const int h = picref->height >> ((plane == 1 || plane == 2) ? geq->vsub : 0);
if (!src)
return 0;
xi = x = av_clipf(x, 0, w - 2);
yi = y = av_clipf(y, 0, h - 2);
x -= xi;
y -= yi;
return (1-y)*((1-x)*src[xi + yi * linesize] + x*src[xi + 1 + yi * linesize])
+ y *((1-x)*src[xi + (yi+1) * linesize] + x*src[xi + 1 + (yi+1) * linesize]);
}
//TODO: cubic interpolate
//TODO: keep the last few frames
static double lum(void *priv, double x, double y) { return getpix(priv, x, y, 0); }
static double cb(void *priv, double x, double y) { return getpix(priv, x, y, 1); }
static double cr(void *priv, double x, double y) { return getpix(priv, x, y, 2); }
static double alpha(void *priv, double x, double y) { return getpix(priv, x, y, 3); }
static const char *const var_names[] = { "X", "Y", "W", "H", "N", "SW", "SH", "T", NULL };
enum { VAR_X, VAR_Y, VAR_W, VAR_H, VAR_N, VAR_SW, VAR_SH, VAR_T, VAR_VARS_NB };
static av_cold int geq_init(AVFilterContext *ctx)
{
GEQContext *geq = ctx->priv;
int plane, ret = 0;
if (!geq->expr_str[0]) {
av_log(ctx, AV_LOG_ERROR, "Luminance expression is mandatory\n");
ret = AVERROR(EINVAL);
goto end;
}
if (!geq->expr_str[1] && !geq->expr_str[2]) {
/* No chroma at all: fallback on luma */
geq->expr_str[1] = av_strdup(geq->expr_str[0]);
geq->expr_str[2] = av_strdup(geq->expr_str[0]);
} else {
/* One chroma unspecified, fallback on the other */
if (!geq->expr_str[1]) geq->expr_str[1] = av_strdup(geq->expr_str[2]);
if (!geq->expr_str[2]) geq->expr_str[2] = av_strdup(geq->expr_str[1]);
}
if (!geq->expr_str[3])
geq->expr_str[3] = av_strdup("255");
if (!geq->expr_str[1] || !geq->expr_str[2] || !geq->expr_str[3]) {
ret = AVERROR(ENOMEM);
goto end;
}
for (plane = 0; plane < 4; plane++) {
static double (*p[])(void *, double, double) = { lum, cb, cr, alpha };
static const char *const func2_names[] = { "lum", "cb", "cr", "alpha", "p", NULL };
double (*func2[])(void *, double, double) = { lum, cb, cr, alpha, p[plane], NULL };
ret = av_expr_parse(&geq->e[plane], geq->expr_str[plane], var_names,
NULL, NULL, func2_names, func2, 0, ctx);
if (ret < 0)
break;
}
end:
return ret;
}
static int geq_query_formats(AVFilterContext *ctx)
{
static const enum PixelFormat pix_fmts[] = {
AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P,
AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV440P,
AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_GRAY8,
AV_PIX_FMT_NONE
};
ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
return 0;
}
static int geq_config_props(AVFilterLink *inlink)
{
GEQContext *geq = inlink->dst->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
geq->hsub = desc->log2_chroma_w;
geq->vsub = desc->log2_chroma_h;
geq->planes = desc->nb_components;
return 0;
}
static int geq_filter_frame(AVFilterLink *inlink, AVFrame *in)
{
int plane;
GEQContext *geq = inlink->dst->priv;
AVFilterLink *outlink = inlink->dst->outputs[0];
AVFrame *out;
double values[VAR_VARS_NB] = {
[VAR_N] = geq->framenum++,
[VAR_T] = in->pts == AV_NOPTS_VALUE ? NAN : in->pts * av_q2d(inlink->time_base),
};
geq->picref = in;
out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
av_frame_copy_props(out, in);
for (plane = 0; plane < geq->planes && out->data[plane]; plane++) {
int x, y;
uint8_t *dst = out->data[plane];
const int linesize = out->linesize[plane];
const int w = inlink->w >> ((plane == 1 || plane == 2) ? geq->hsub : 0);
const int h = inlink->h >> ((plane == 1 || plane == 2) ? geq->vsub : 0);
values[VAR_W] = w;
values[VAR_H] = h;
values[VAR_SW] = w / (double)inlink->w;
values[VAR_SH] = h / (double)inlink->h;
for (y = 0; y < h; y++) {
values[VAR_Y] = y;
for (x = 0; x < w; x++) {
values[VAR_X] = x;
dst[x] = av_expr_eval(geq->e[plane], values, geq);
}
dst += linesize;
}
}
av_frame_free(&geq->picref);
return ff_filter_frame(outlink, out);
}
static av_cold void geq_uninit(AVFilterContext *ctx)
{
int i;
GEQContext *geq = ctx->priv;
for (i = 0; i < FF_ARRAY_ELEMS(geq->e); i++)
av_expr_free(geq->e[i]);
}
static const AVFilterPad geq_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = geq_config_props,
.filter_frame = geq_filter_frame,
},
{ NULL }
};
static const AVFilterPad geq_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
AVFilter avfilter_vf_geq = {
.name = "geq",
.description = NULL_IF_CONFIG_SMALL("Apply generic equation to each pixel."),
.priv_size = sizeof(GEQContext),
.init = geq_init,
.uninit = geq_uninit,
.query_formats = geq_query_formats,
.inputs = geq_inputs,
.outputs = geq_outputs,
.priv_class = &geq_class,
};
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